NEW YORK (AP) ¿ GigaMedia Ltd. said Wednesday that it is selling a majority stake in its online gambling software business to Mangas Gaming, a sports betting and online gaming operator.

Magna will pay $100 million at closing for its 60 percent stake in the operations, as well as later payment based on the unit's fair value in 2012.

GigaMedia, an online gaming and software company based in China, will keep 40 percent ownership of the business and has the option to sell all or part of its stake to Mangas starting in 2013. Mangas will be able to buy any remaining shares GigaMedia owns beginning in 2015.

The transaction makes GigaMedia's Everest Poker the primary poker site for Mangas.

GigaMedia anticipates a "substantial gain" from the sale, which is expected to close in the first quarter of 2010.

U.S.-traded shares of GigaMedia gained 49 cents, or 13 percent, to $4.28 in premarket trading. The stock has traded in a range of $3.49 to $7.73 over the last year.

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